I have a Sandisk Cruzer Edge 16GB Flash Drive. I use it with two computers, an iMac and a Macbook Air, both using OS X 10.8.2. I recently loaded about 10GB of files onto it. I have now deleted those files. However Finder is still showing the Flash Drive as carrying 10.8 GB of files and having only 5.2 GB available. When I try to save a 10 GB folder to the Flash Drive, I get a message saying that there is not enough available space.
How do I delete uploaded files from the Flash Drive so that I can re-use the whole 16 GB?